Physicists have just broken the entanglement record by creating a quantum register made of 20 entangled and controllable qubits.
Quantum entanglement is one of the most studied processes by physicists for its wide range of theoretical applications. To have an operational quantum computer, we need a large number of entangled particles (qubits) that are inherently linked. In other words, we need controllable qubits.
Now, a team of German and Austrian physicists has achieved a quantum milestone in that regard.
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Multi-Particle Entangled Systems
Qubits are to quantum computing what bits are to classical computing.
Future quantum infrastructures will need large numbers of entangled qubits so superposition and other quantum magic can take place.
Combining controllable qubits in a stable quantum arrangement, or register, is a more arduous technical task than what it might sound.
To name a few of the technical hurdles that come with building an operational quantum system, qubits need to be in a completely isolated environment and at a temperature near absolute zero.
Thus, the research team created a 20-Qubit entanglement for the first time.
The researchers used 20 calcium ions arranged in a line as qubits and entangled them with laser beams.
Each of the calcium atoms was shown to be able to entangle with up to four other qubits in the register.
Record-Breaking Entangled System With 20 Individually Controllable Qubits
Multi-particle entanglement has been done before by the same team and other researchers.
However, what differentiates this experiment, apart from the number of entangled qubits in the system, is that researchers were able to control each qubit individually.
“There are quantum systems such as ultra-cold gases in which entanglement between a large number of particles has been detected,” Friis said Nicolai Friis, lead author of the study. “However, the Innsbruck experiment is able to address and read out every single quantum bit individually.”
Friis’ last sentences shed some light on the current state of quantum computers.
In all these systems, unlike the present 20-qubit system, qubits can’t be controlled and read individually.
How researchers built a quantum system of 20 individually controllable qubits was the subject of their experiment. They explain in detail in the journal Physical Review X.
Above all, this spells a new approach in the realm of quantum infrastructures. Now, the aim will be to build smarter, not bigger.